1. Field of the Invention
The present invention relates to a communication system having in-vehicle terminals and a center (an information center) interconnected by radiocommunication. Moreover, the present invention relates to an in-vehicle terminal employed in the communication system.
2. Description of the Related Art
There is a communication system in which computer programs, to be installed in in-vehicle terminals, are distributed from a center by radiocommunication or the like. In the communication system, when a user wants to install a program such as a navigation system or video game in his/her in-vehicle terminal, or when a user wants to update an installed program, the user issues a request for downloading a program from his/her in-vehicle terminal to the center. The center downloads the requested program to the in-vehicle terminal by radiocommunication or the like.
At this time, the center wants to check if downloading the program to the in-vehicle terminal has been completed normally. Otherwise, the center wants to check if the downloaded program is operating normally while being compatible with the software and hardware environment of the in-vehicle terminal. Through this checking, the center confirms that the program has been distributed to the user. At the same time, the in-vehicle terminal can be kept safe. Moreover, after checking, the center can charge the user for the service.
In contrast, in conventional communication systems, a center does not have a means for performing the checking. After a program is delivered to an in-vehicle terminal, the program is at the user's disposal. The center cannot therefore sell a program even after confirming that the program satisfies the user. Moreover, even if an abnormality occurs during downloading or after activation of a program, the center cannot cope with it swiftly.